1. Field of the Invention
The present invention relates in general to waste water drainage systems. More particularly, the present invention relates to methods and apparatus utilized to remove contaminants by absorption from municipal storm drains.
1. Description of the Prior Art
Streets and highways channel runoff water into storm sewers which carry the runoff into water shed areas such as rivers, lakes, streams, etc. The storm sewers function to remove runoff water before the runoff accumulates to a level which causes damage or inconvenience. Contaminants carried by the runoff water are transported in to the lakes and streams along with the water. This contributes to the over all pollution of the watershed areas. Typically street runoff water is channeled to the edge of the street where at selected intervals a collection box is placed to remove the water from the street level to a subterranean sewer. The runoff water includes contaminants and debris. A large number of contaminants such as oil can be filtered out of the water. A simple passage of runoff water through a filter selected to remove pollutants will clog with debris in a short time requiring excessive maintenance and when the cloging is severe the purpose of the storm drain can be negated causing the runoff to backup above ground and flood surrounding area. A requirement for a contaminant filter is that the filter must be able to pass large debris through to prevent the filter from clogging, while removing the desired contaminants. A number of filters have been proposed which filter debris or provide a device that is easily cleaned when clogged. Governmental regulations have recently placed constraints on storm runoff to reduce the contribution of runoff water to the overall pollution of lakes and streams. Various filter systems have been proposed for use in storm drains but none remove contaminants through absorption.
Numerous innovations for Storm Drain Filter have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted.
In U.S. Pat. No. 5,480,254, titled Storm Drain Box Filter and Method of Use, invented by James L. Autry and Jimmy N. Whitley, this invention is a box filter used in conjunction with newly constructed storm drains and the like to prevent undesirable amounts of sediment and other debris carrier by storm runoff from entering the storm drain. Upper and lower frames are provided with expanded metal interior and exterior sidewalls extending therebetween. The box-like structure has an open bottom, reinforcing plates adjacent the connection of a lift handle and corner braces to add rigidity to the system. An aggregate such as crushed stone is placed between the interior walls and exterior walls of the filter and acts as a filter media for the sediment of the debris. This filter is reusable without loss of its filtering qualities due to its rugged construction and back flushable filter medium.
The patented invention is a debris filter. It does not filter fluid contaminants. The present invention passes debris but filters fluid contaminants such as oil.
In U.S. Pat. No. 5,405,539, titled Storm Drain Filter System, invented by Thomas W. Schneider, a filter system for insertion and assembly in a storm drain collection box. The filter includes a frame having a removable back and legs for easy assembly in the storm drain collection box. The frame includes a bed portion which is telescopic so as to be expandable to accommodate the width of the collection box. A sheet of filter medium is placed on the filter bed and back, and the filter frame is then urged against the front of the collection box by pneumatic cylinders. Silt and other debris collects in the filter compartment until full, and then the excess drainage water overflows unrestricted over the back of the filter frame.
The patented invention filters storm water debris and silt through a trap comprising a mesh and a filter medium sheet. The patented invention is installed in existing storm drains. When the filter is full, water is permitted to by pass the filter. The patented invention does not absorb fluid contaminants. The filter medium is comprised of a sheet supported by a screen like structure. The filter medium is not absorbent. The present invention filter passes debris but filters absorbable fluid contaminants such as oil. Water is directed along a maze path of filters which absorb contaminants but permit debris to bypass the filter. The filters are supported on trays which are removable when the entire device is removed from the storm drain structure.
In U.S. Pat. No. 5,284,580, titled Refuse Collecting Frame for Sewer, invented by Shyh-Yuan Shyh, a refuse collecting frame for a drainage sewer, particularly a frame placed beneath a cover of a sewer drainage opening to accumulate refuse and permit easy disposal of refuse accumulated therein in order to prevent blockage of the sewer. The refuse collecting frame includes a frame body and a refuse collecting basin. The frame body is preferably a rectangular or cubic frame structure having a dimension corresponding to the opening of the sewer drain. A filtering net or a porous board with a plurality of penetrating holes is incorporated at each lateral side and bottom of the frame. A plurality of right-angled hangers are formed at spaced positions along the upper edges of an open upper side of the frame for firmly hanging the frame on a sewer opening by positioning the right-angled hangers on a stepped portion formed along edges of the sewer opening beneath a separate storm drain sump which has a fluid outlet through a wall of the sump, the filter includes a bag-like body member having a cylindrical body portion fabricated from resilient mesh-like synthetic material. A base portion of the filter defines a toroid-shaped section. A weighted material is placed within the toroid-shaped section. Wedge-shaped spacers are axially aligned and secured to an outer face of the cylindrical body portion of the filter. A suspension plate is secured to the body member to support the filter in the storm drain sump.
The patented invention functions to remove debris from storm drains. It does not have an absorbent means.
Numerous innovations for Storm Drain Filter have been provided in the prior art that are adapted to be used. Even though these innovations may be suitable for the specific individual purposes to which they address, they would not be suitable for the purposes of the present invention as heretofore described.